Fuse switch



FUSE SWITCH Filed March 17, 1959 5 Sheets-Sheet l March 3, 1942.

T. F. JOHNSON FUSE SWITCH Filed March 17, 1939 3 Sheets-Sheet 2 3, 1942. F JQHNSON 2,274,898

FUSE SWITCH Filed March 17, 1959 3 SheetS-Sheet 3 Patented Mar. 3, 1942 UNITED STATES PATENT OFFICE FUSE SWITCH Tomlinson F. Johnson, Atlanta, Ga.

Application March 17, 1939, Serial No. 262,521

7 Claims.

This invention relates to fuse switches and, among other objects, aims to provide important improvements in gang operated fuse switch assemblies having removable fuse units connected to be manually operated simultaneously to open or close a multiphase circuit and designed to permit any one or all of the fuse units to drop out automatically when an overload occurs in the circuit. Another aim is to provide a gang fuse switch assembly wherein the individual fuse units, when blown, are adapted to swing in one plane through approximately 180 so that they hang vertically and downwardly and may easily be removed and replaced. This invention involves certain important improvements in the type of fuse switch assembly disclosed and claimed in my copending application Ser. No. 222,528, filed August l, 1938, now Patent No. 2,158,722.

Other aims and advantages of the invention will appear in the specification, when considered in connection with the accompanying drawings, wherein:

Fig. 1 is a fragmentary front elevation of a gang fuse switch assembly embodying the improvements;

Fig. 2 is a sectional view taken on the line 22 of Fig. 1 showing one of the fuse switch assemblies in side elevation;

Fig. 3 is a sectional view taken on the line 3-3 of Fig. 1; and

Figs. 4, and 6 are sectional views taken on the lines 44, 5-5 and 6-43, respectively, of Fig. 2.

Referring particularly to the drawings, the switch fuse installation, there shown, is quite similar in its operation to that shown and described in the aforesaid copending application. It embodies a series of fused switch units adapted to drop out individually and to be operated simultaneously as a gang switch. The fused switch units are arranged vertically to drop out in one plane and to be operated manually in another plane at right angles to the first plane. As the assembled switch fuse units are identical, only one requires description. In Fig. 1, two such assemblies are shown merely to illustrate the gang operation, but it is understood that three units will be employed in three phase circuits.

Referring to Figs. 2 and 3, the assembly is there shown as embodying an expulsion type fuse unit l0 which may be and preferably is substantially the same as that disclosed in my copending application Ser. No. 180,423, filed Dec. 17, 193'7now Patent 2,216,843. It is carried by a rotatable insulator II and is adapted to close the circuit through a contact carried by a stationary insulator I2, both insulators being mounted on a vertical support such as a structural channel [3. The supporting structure for the assembly is carried by a metal cap bracket 14 bolted to the rotatable insulator H. In this instance, a pair of L-shaped bracket arms 15 is suitably secured to the cap bracket 14 and these arms have notched bearings I6 for trunnions IT on a saddle shaped member l8 embracing the back side of the fuse tube at its lower end. The forward ends of the bracket arms l5 are shown as having upwardly curved guiding fingers I!) to facilitate insertion of the trunnions in the open, notched bearings and the arrangement of the notches is such that the trunnions cannot swing out of them when the fuse unit swings to its drop out position.

As disclosed in my aforesaid copending application Ser. No. 180,423, the saddle 18 has a rearward extension terminating in a hook eye 20 and the back face of this extension provides the main lower terminal 2| for the fuse, the fuse wire 22 being connected to said extension and trained around a cam-shaped guide element 23 in the lower end of the fuse tube. The saddle member carries two upstanding integral arms 24 pivoted at their upper ends to similar arms 25 which are integrally connected to a collar 26 on the fuse tube. The arrangement is such that the arms provide a break jointed stiff leg to initiate the drop out movement of the fuse unit. The upper end of the fuse tube carries an ordinary collar 21 presenting a hook eye 28 on its front side and a fuse terminal in the form of a disk 29 is shown as being screw threaded into the upper end of the collar. This contact disk is adapted to close the circuit through a universally movable contact member 30 which is carried by the upper or stationary insulator l2 and which Will presently be described.

The bracket I4 is shown as carrying a swingably mounted line terminal arm 3| suitably connected thereto by a bolt 32 and preferably having anti-friction bearings, as clearly shown in Fig. 3. The idea is to permit the insulator to rotate to operate the fus assembly as a switch without bending the line conductor. The bracket I4 also carries a vertical extension 33 to which is pivotally connected a bifurcated plate 34 straddling the fuse unit I0 just above the collar 26 and adapted not only to guide the fuse unit into its switch closing position but also to hold the fuse unit rigid with respect to the insulator II when the insulator is rotated to operate the fuse unit as a switch blade. Th plate is preferably formed of a channel shaped casing and the bifurcation formed in the outer end of the web to present outwardly flared guiding edges 35. The flanges at the outer ends present cam-shaped faces 36 and cooperate with trunnions 31 on the back side of the collar 25, the arrangement being such that the trunnions contact and ride on the cam faces as the fuse unit swings to its closed position and the flanges also have notches 38, the back faces of which limit the closin swinging movement of the trunnions. The plate is biased to rest in the position shown in Figs. 2 and 3 by engagement with a ledge or shoulder 39 projecting forwardly from the upper end of the extension 33. A coil spring 3 is connected to the plate in front of the shoulder 355 and also to a pivoted combination contact member and bumper M the upper end of which has an opening to receive the coil spring and the front face of it is arranged to contact with the fuse terminal H on the saddle extension 18. This member is shown as being pivoted on a shaft or pin 42 extending through two downwardly extending arms 43 of the L-shaped bracket members 55. The back side of the contact member ll shown as carrying a braided flexible conductor connected to the extension 33 and thence, to the depending swinging terminal arm 3!. The normal position of the contact member is substantially vertical but when the fuse unit is closed it is swung in a counterclockwise direction to the position shown in Fig. 2, thereby placing the coil spring under tension and the spring exerts an outward force through the terminal 2i, tending to break the knee joint formed by the arms 24 and 25. The lower end of the contact member ll extends downwardly and slightly forwardly, having a cross bar or bumper element adapted to be struck by the upper arms :25 when the fuse unit swings downwardly to the drop out position indicated by dotted line in Fig. 3. When it strikes the bumper bar it tends to swing the contact member clockwise against the tension of the spring.

Referring to the upper contact 33, it is shown being carried by a forwardly extending horizontal arm 33 havin a wide rear end pivoted on a shaft 37 carried by a cap plate 38 on the fixed insulator 52. A fixed conductor terminal 49 is connected to the upper end of the cap plate. The arm is biased to swing downwardly by a coil spring 5 which exerts downward or drop out pressure on the fuse unit. The downward movement of the arm is limited by integral depending projections or ears El engaging stop lugs 52 on the cap 18.

In this example, the contact member is in the form of a casting suspended for slight universal movement on the outer end of the arm 55. It is shown as having two upwardly extending fingers 53 loosely guided in opposit notches in the arm and a pin 55 through the upper ends of the fingers supports the contact when the fuse unit is open. The contact member is in the form of an L-shaped casting having bifurcated upwardly bent channel-shaped guides 56 and 51 arranged to guide the contact disk on the fuse unit into its switch closing position, as shown in Fig. 3. The upper wall of the contact member is shown as having a hollow upstanding boss 53 adapted to engage the lower end of an adjustable screw threaded stem 59 in the outer end portion of the arm and held in its adjusted position by a lock nut 60, as clearly shown in Fig. 3. This pin limits the upward movement of the contact member tit but permits it to have limited universal movement so that its lower contact face can adjust itself in face-to-face engagement with the contact disk 29.

The guides 56 and 5'. are shown as being inclined and are channel-shaped with their flanges depending vertically to confin the contact disk. They are flared and the webs have longitudinal central notches or slots 61 which serve as guides to center the contact disk 29 upon its initial switch closing movement while the rounded rear edge of the disk rides in the respective notches. At the back side of the contact member, there is shown a stop flange 62 for the disk 29 to strike when the fuse unit is swung to its closed position from its drop out position. A braided or flexible conductor 63 is shown as being connected to the rear face of this flange and to the terminal arm :9 on the cap plate 48.

As explained in my aforesaid copending application Ser. No. 222,528, a gang of the fuse units is adapted to be manually operated by an ordinary lever connected to impart rotation to the rotatable insulators I l conveniently by means of cranks 6 and an operating link or rod 65, it being understood that the fuse units are swung to the right, as viewed in Fig. 1, when operated as a switch. Incidentally, the opening and closing movement of the fuse units, when operated as a gang switch, is limited by stops or adjustable screws -56 coaoting with a fixed abutment 61, as shown in Fig. 2.

Referring to the operation of the fuse assembly, when the fuse drops out, it will be noted that drop out or endwise pressure is exerted on the fuse unit through the upper contact member by means of the spring 50. Also, when the fuse element blows, the rearward extension or contact member 2| on the saddle I8 is pressed forwardly by the tension of the spring to break the knee joint between the arms 24 and 25 permitting the lower end of the fuse unit to swing forwardly and downwardly. The initial drop out impulse imparted to the fuse tube will very quickly break the circuit. When the upper contact of the fuse unit drops away from the upper switch contact, the arm 46 will swing downwardly to a position slightly below the horizontal and will remain in that position until the fuse unit is again closed. When the fuse unit drops out, it swings to its vertical position upside down and strikes the bumper bar on the contact member 4|, the tension spring 40 limiting its backward swinging movement and restoring it to substantially the position shown in dotted lines in Fig. 3, in which position a lineman can easily reach the hook eye 29 and lift out the fuse unit from its notched bearings Hi either to replace it or to re-fuse it. The gang operation of the fuse units as switches has just been described and requires no further explanation, except that the arms 46 will withstand all ordinary shocks incident to switch closing movements.

From the foregoing description, it will be seen that the mechanism is relatively simple and rugged in its construction. The fuse units do not require any special locking latches to hold them in their closed positions. They are easily accessible for replacement and re-fusing. Moreover, the supporting mechanism for the fuse units can be standardized and manufactured at a relatively low cost. In fact, such fuse switches have already demonstrated their commercial practicability in connection with electrification projects.

Obviously, the present invention is not restricted to the particular embodiment thereof herein shown and described. Moreover, it is not indispensable that all the features of the invention be used conjointly, since they may be employed advantageously in various combinations and sub-combinations.

What its claimed is:

1. A fuse switch assembly comprising, in combination, an upper insulator carrying a contact; a lower pivoted insulator carrying bearing means; a fuse unit removably mounted at one end in said bearing means and normally engaged at the other end with said contact; a terminal member pivotally connected to the lower end portion of the unit; a pivoted spring urged contact member on the lower insulator engaging said terminal member and biased to swing the lower end of the unit outwardly in one direction when the fuse blows; an integral bumper on the lower end of said pivoted contact member adapted to be engaged by said unit after it drops out; and manualy operable means connected to swing the fuse unit as a switch blade in another direction.

2. A fuse switch assembly comprising, in combination, an upright support; an upper stationary insulator having a contact; a lower rotatable insulator; a bracket member carried by the lower insulator; a fuse unit removably and pivotally connected to the bracket member and connected to drop out in one direction when the fuse blows and adapted to be swung in another direction as Y a switch blade; a terminal member carried by the lower end of the fuse unit; a pivoted bifurcated latch member connected to the bracket and coacting with the fuse unit to hold it fixed relative to said bracket when the fuse unit is swung as a switch blade; a combined contact and bumper member carried by the bracket and coacting with said terminal member and the fuse unit; and a single spring connected between said contact and bumper member and said latch member normally holding the latch in locking engagement with the fuse unit and the contact in engagement with said terminal.

3. A fuse switch assembly comprising, in combination, an upright support; an upper fixed insulator on said support; a lower rotatable insulator carried by said support; a fuse unit pivotally mounted with respect to said rotatable insulator connected to drop out in one direction and adapted to be swung as a switch blade in another direction; a universally mounted contact member carried by said fixed insulator and having outwardly flared guide-ways for the upper fuse terminal; and a spring urged arm supporting said contact member and connected to exert drop out pressure on said fuse unit when it is in closed position.

4. A fuse switch assembly comprising in combination, an upright support; an upper fixed insulator on said support; a lower rotatable insulator carried by said support; a fuse unit pivotally mounted with respect to said rotatable insulator connected to drop out in one direction and adapted to be swung as a switch blade in another direction; a spring biased substantially horizontal arm pivotally mounted on said upper insulator; and a contact member suspended for limited universal movement from said arm and having guide ways for the fuse terminal.

5. A fuse switch assembly comprising, in combination, a vertical support; an upper insulator secured to the support and having a resilient contact; a lower insulator parallel with the upper insulator mounted for rotation about its own axis on the support; a fuse unit removably and pivotally mounted on the lower insulator; a terminal member on the upper end of the fuse unit normally engaging said resilient contact; a terminal member on the lower end portion of the unit; a fuse element connected to the lower terminal member and arranged to hold the upper fuse terminal normally engaged with the resilient contact; a spring urged pivoted contact member on the lower insulator engaged with the lower terminal and biased normally to kick out the fuse unit and cause it to drop out in one direction when the fuse element blows; and manually operable means connected to swing the fuse unit in another plane to disengage it from the resilient contact.

6. A fuse switch assembly comprising, in combination, a vertical support; an upper horizontal insulator secured to the support and having a resilient contact member; a lower horizontal insulator parallel with the upper insulator mounted for rotation about its own axis on the support and having open bearings; a fuse unit including a pair of arms having trunnions removably and pivotally mounted in said bearings; a terminal on the upper end of the fuse unit adapted to engage said resilient contact member; a fuse element connected to said arms normally holding the upper fuse terminal engaged with the resilient contact when the fuse unit is in closed position; a pivoted spring urged member biased normally to kick out the lower end of the fuse unit and cause it to swing downwardly in one direction when the fuse element blows; and manually operable means connected to swing the fuse unit in another plane to disengage it from the resilient contact.

'7. A *fuse switch assembly comprising, in combination, a vertical support; an upper horizontal insulator secured to the support; a spring biased pivoted arm mounted on said insulator; a contact member loosely suspended from said arm; a lower horizontal insulator parallel with the upper insulator mounted for rotation about its own axis on the support and having open bearings; a fuse unit including a saddle member having trunnions removably and pivotally mounted in said bearings; a terminal on the upper end of the fuse unit adapted to engage said resilient contact member; a fuse element secured in said saddle member normally holding the upper fuse terminal engaged with the resilient contact when the fuse unit is in closed position; a pivoted spring urged member biased normally to cause the fuse unit to drop outwardly and downwardly in one direction when the fuse element blows; and manually operable means connected to swing the fuse unit in another direction to disengage it from the resilient contact.

'TOMLINSON F. JOHNSON. 

